Most modern vehicles include inflatable restraint apparatus having deployable airbags positioned in many locations throughout an automotive vehicle. Generally, an interior panel includes a deployment door formed into the panel which is designed to break free upon deployment of the airbag. A supporting structure behind the interior panel typically contains flexible tethers or metal hinges, which in combination with the deployment door is designed to let the airbag deploy in a very short duration.
A primary aim of the airbag assembly is to control the opening of the deployment door to avoid break explosion and the possibility of flying parts. Clean deployment is provided, in part, through aggressive pre-weakening of the outline of the deployment door to form a seam (typically by laser scoring, mechanical scoring, etc.) in order to insure clean airbag performance. Many airbag assemblies also include ribs formed directly into the substrate of the instrument panel and its deployment door such that the airbag assembly may be directly attached thereto. These ribs are fairly tall and extend through slots or apertures in the airbag assembly and are heat staked or otherwise deformed to attach the components.
Unfortunately, the provision of ribs or other structures for heat staking directly to the substrate of the instrument panel can result in exterior surface appearance defects during molding. Similarly, the pre-weakening of the deployment door's seam can cause potential surface appearance defects, either before or after the scoring procedure. The characteristics of the seam may also change over a long period of time due to exposure to environmental conditions such as UV rays, other light rays, heating or other temperature changes. Finally, the heat stakes represent an additional structure which must be controlled for flying parts during airbag deployment.
Accordingly, there exists a need to provide an inflatable restraint apparatus and airbag assembly for a motor vehicle which overcomes the above-noted drawbacks of using a heat staking operation to connect structural components and which reduces or eliminate the need for aggressive pre-weakening of the seam defining the deployment door in the interior panel.